The principal subject of the contribution is analyzed within the context of the general doctrine of the Latin and Greek verb. This general doctrine underwent ba&#173;sic changes in the work of the most prominent Roman grammarians. The inter&#173;play of different philosophical and rhetorical doctrines had a large impact on the evolu&#173;tion of grammatical theory. At the beginning of the period we see a Latin word qualitas, which was related with the Stoic Greek notion poi&#243;t&#275;s, being used as a term for modal forms of the verb. This particular definition of modal forms seems to be due to Pliny the Elder. Having reconsidered the Stoic doctrine of speech acts and, more generally, the verbal expression of movement and state, the grammarians of the first century AD began to use the adjective horistik&#243;s and its Latin coun&#173;terpart finitivus as a term for the indicative mode. Terentius Scaurus (fl. bet&#173;ween 117 and 138 AD) intro&#173;duced the term modus instead of qua&#173;litas in the field of modal forms. Aware of the meaningless use of the term finitivus in some special case, Scaurus replaced it with the term pronuntiativus, which had been taken over from rhetoric and which had a larger meaning than its Greek counterpart apophan&#173;tik&#243;s. Moreover, he replaced the term ordo with the more particular term coniuga&#173;tio&#65279; in the description of conjugations. The doctrine of Flavius Caper (2nd half of the 2nd c. AD) marked a return to a number of Stoic ideas. The unfortunate finiti&#173;vus was replaced by indicativus in order to say a word with a similar but larger meaning. Caper, however, thought it inappropriate to use the term indicativus with regard to the future that did not yet exist. So he intro&#173;duced a special mode promis&#173;sivus. In the meantime he replaced the term infinitivus and its twin infinitum with modus per&#173;petuus. The term indicativus, however, seems to be the only invention of Caper to have survived in the posterior tradition.